1. Field of the Invention
The present invention relates generally to a music training apparatus using a recording medium memorizing an accompaniment and a model singing or play sound, and more particularly to a music training apparatus capable of adjusting the interval (i.e. key) of the accompaniment in accordance with user's singing or play compass.
2. Description of the Related Art
A karaoke machine, known as a conventional music training apparatus, is a musical device having been developed in Japan for entertainment, which reproduces the accompaniment music memorized in a recording medium and mixes this accompaniment music with a user's musical signal: for example, singing or playing sound collected through a microphone. Recent development in this karaoke machine allows users to freely change the key of the accompaniment music.
For example, Japanese Patent Provisional Publication No. 204095/84 discloses such a conventional karaoke machine equipped with the key adjusting device. However, this conventional karaoke machine forces the user to perform complicated adjusting operations.
More specifically, this conventional karaoke machine comprises: frequency analyzing means for analyzing the frequency of a sound signal to make a judgement as to whether this sound signal is high or low; compass checking means for checking compasses of both the accompaniment music signal and the user's singing signal beforehand on the basis of the judgement result of the frequency analyzing means; frequency shift amount determining means for determining a frequency shift amount on the basis of the compasses of said two signals checked by said compass checking means; and frequency shift means for shifting the frequency of the accompaniment music signal in accordance with the shift amount determined by said frequency shift amount determining means.
An operation of above conventional karaoke machine will be explained below.
First of all, the frequency of the music signal to be reproduced from the recording medium is analyzed by the frequency analyzing means. Then, in accordance with the result of this frequency analysis, both the most highest and lowest sounds are detected by the compass checking means.
This frequency analysis requires the user to successively pronounce "do, re, mi, - - -" sounds so that the compass checking means can correctly detect the user's range of voice.
Then, the frequency shift amount determining means compares the compass between the recording medium's music sound and the user's voice, so as to determine a suitable frequency shift amount. For example, if the compass of the recording medium's music sound is higher than that of the user's voice, the frequency shift amount is determined to effectively reduce the key of the recording medium. Accordingly, since the frequency shift means changes the key of the recording medium in accordance with the frequency shift amount, it becomes possible to reproduce the sound so as to fit to the user's range of voice.
However, this conventional karaoke machine disadvantageous in that the user is forcibly required to successively pronounce "do, re, mi, - - -" sounds until the compass checking means correctly detects the user's range of voice. In fact, it will take a long time before actually allowing the user to sing a song. Especially, such a complicated and time-consuming operation will not be acceptable for the people who are enjoying a karaoke party using the same karaoke machine.